How to automatically fill in form fields/ (suggest) phrases from database

This is probably not an ecart question, maybe it is not even a Webassist question, but here it goes.

On the address form our customers have to enter their country. First I wanted to do that with a drop down menu, but there are just to many countries, and I don't want to exclude any countries, just because they are too little.

Now I would like the field to fill in the information as the customer types, for example the customer starts typing "b", and the first country that starts with "b" is filled in. Then the customer types in "e" and "Belgium" is filled in. Then the customer types "r", and "Bermuda" is suggested, and so forth.

I would store the country names in the database in order to be able to filter them by language.

I saw this done on the Canadian Yellow Pages, and it looks pretty good.

Could anyone help me with this?